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The male sterile G cytoplasm of wild beet displays modified mitochondrial respiratory complexes
Author(s) -
Ducos Eric,
Touzet Pascal,
Boutry Marc
Publication year - 2001
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.2001.01017.x
Subject(s) - alternative oxidase , cytoplasmic male sterility , biology , cytochrome c oxidase , cytoplasm , sterility , respiratory chain , protein subunit , mitochondrion , oxidase test , mitochondrial dna , organelle , mitochondrial respiratory chain , western blot , microbiology and biotechnology , gene , genetics , biochemistry , enzyme
Summary Cytoplasmic male sterility (CMS) in higher plants has been mainly studied in cultivated species. In most cases, pollen abortion is linked to the presence of an additional mitochondrial polypeptide leading to organelle dysfunction in reproductive tissues. In wild beet, both CMS and hermaphrodite plants coexist in natural populations. The G cytoplasm is widely distributed along the Western European coast, and previous genetic studies have demonstrated that this cytoplasm confers male sterility in beet. In the present study, we have identified two mutations of G mitochondrial genes, each of which results in the production of a respiratory chain complex subunit with an altered molecular weight; the NAD9 subunit has a C‐terminal extension while the COX2 subunit has a truncated C‐terminus. NADH dehydrogenase activity was unchanged in leaves, but cytochrome c oxidase activity was reduced by 50%. Moreover, Western blot analyses revealed that alternative oxidase was more abundant in male sterile G plants than in a fertile control ( Nv ), suggesting that this alternative pathway might compensate for the cytochrome c oxidase deficiency. Implications of respiratory chain changes and a putative link with CMS are discussed.